using FrameworkDAL.DTO.EIPConversation;
using System.Text;

namespace FrameworkBLL.EIPConversation.EIPHandlers.EIPEngine.FlowEngine
{
    /// <summary>
    /// Converts EIPStructuredDataDTO to a plain-text string for text-only channels
    /// (WhatsApp, SMS, Telegram). Called by channel handlers when StructuredData is present.
    /// </summary>
    public static class EIPTextFormatter
    {
        /// <summary>
        /// Produces a human-readable text representation of structured data.
        /// TABLE:  one record per block, field labels with values, records separated by ---
        /// CARD:   single record displayed as label: value pairs
        /// LIST:   numbered list using the first field value per row
        /// </summary>
        public static string FormatAsText(EIPStructuredDataDTO data)
        {
            if (data.Rows.Count == 0)
                return "(No data)";

            var sb = new StringBuilder();

            switch (data.Type.ToUpperInvariant())
            {
                case "LIST":
                    for (int i = 0; i < data.Rows.Count; i++)
                    {
                        var row = data.Rows[i];
                        var firstVal = data.Fields.Count > 0 && row.TryGetValue(data.Fields[0].Field, out var fv)
                            ? fv : string.Join(", ", row.Values);
                        sb.AppendLine($"{i + 1}. {firstVal}");
                    }
                    break;

                case "CARD":
                    AppendRecord(sb, data.Fields, data.Rows[0]);
                    break;

                default: // TABLE
                    for (int i = 0; i < data.Rows.Count; i++)
                    {
                        if (i > 0) sb.AppendLine("---");
                        AppendRecord(sb, data.Fields, data.Rows[i]);
                    }
                    break;
            }

            if (data.IsTruncated)
                sb.AppendLine($"(Showing {data.Rows.Count} of {data.TotalCount})");

            return sb.ToString().TrimEnd();
        }

        private static void AppendRecord(
            StringBuilder sb,
            System.Collections.Generic.List<EIPFieldDefinitionDTO> fields,
            System.Collections.Generic.Dictionary<string, string> row)
        {
            foreach (var field in fields)
            {
                var val = row.TryGetValue(field.Field, out var v) ? v : string.Empty;
                sb.AppendLine($"*{field.Label}*: {val}");
            }
        }
    }
}